Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 21 On the Scapuli

Use of the scapula 20

In all animals the arm bone or humerus is articulated to the scapula (S to R of the skeletons); if you imagined a human without scapulae, you could in no way describe the shoulder joint. It is essential to the construction of this joint that the head of the humerus go into the socket of some other bone: and for it to be mobile, that it be braced in another bone as in a kind of base. 21 For the sake of such a socket, a neck protrudes — the cervix of the scapula [collum scapulae] (C, D in figs. 1 and 2) — in the end of which a socket is carved as wide and deep as is useful to the shoulder joint for various quite different motions. This is judged to be without doubt the first and foremost use of the scapulae; another immediately follows, itself not a regrettable one, to wit the fortification and protection of the parts of the thorax covered by the ribs. We watch out for the anterior parts of the thorax and forsee well ahead of time things that are about to strike and wound it, jumping aside in anticipation to avoid what is coming at us, putting up something to shield the chest, or picking up something in our hands with which to defend ourselves. Indeed, we often risk even our bare hands, judging it better that these should be hurt, fractured, crushed, or cut off than allow what could damage the chest to reach it. For the thorax is the organ of respiration, as the lung is also surrounded by it; moreover, the heart is considered the nurturer of innate heat and the seat of an irascible nature, therefore also requiring sturdier defenses. Since the same danger of blows threatens the back of the thorax as the front, but there is not the same foreknowledge of things which can harm it from the rear as in front, there being no eyes in the posterior region, it was quite fitting that Nature fashion some artifice here too and not neglect the posterior surface of the thorax. Whence, as a kind of wall and marvellous rampart she fitted there the vertebrae of the thorax, and she threw up the scapulae like two shields, bucklers, or mighty battlements. She was not unaware that from this yet another use would accrue to man, by which several muscles 22 controlling motions of the arm acquire a place of support where they may best take their origin. Surely it is a work of supreme justice that the same bone is used for such various and quite necessary functions, and that the scapulae are everywhere so formed that they could be thought made exclusively for each of these employments. 23



Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 21 On the Scapuli